[cfe-dev] Wframe-larger-than flag bug

David Blaikie via cfe-dev cfe-dev at lists.llvm.org
Sat Jan 25 19:56:28 PST 2020


Ah, right, sorry I didn't reproduce your steps exactly - thanks for
highlighting the save-temps aspect.

Yeah, testing this with clang trunk (which, on godbolt, is built with
assertions enabled) this crashes the compiler. Something about
frame-larger-than doesn't work with save-temps, which doesn't super
surprise me, -Wframe-larger-than with -fsyntax-only doesn't produce any
warning (frame-larger-than is implemented in the code generation pipeline,
as much as we try to avoid doing that for warnings in clang, this one's an
exception).


On Sat, Jan 25, 2020 at 2:15 PM Ohad Alali <ohad.alali at gmail.com> wrote:

> Thanks for your response.
> I've opened your link and it's seems that clang (trunk) is not handle the
> flag -save-temps=obj. compilation with -save-temps:
> https://godbolt.org/z/-neaMs
> When changing the compiler to clang v0.8, same behaviour as describe
> before.
> with flag -save-temps=obj: https://godbolt.org/z/gzpFGD
> without flag -save-temps=obj: https://godbolt.org/z/5uABvL
>
> Thanks,
> Ohad
>
>
>
> ‫בתאריך שבת, 25 בינו׳ 2020 ב-8:16 מאת ‪David Blaikie‬‏ <‪
> dblaikie at gmail.com‬‏>:‬
>
>> Works for me: https://godbolt.org/z/kMijQ7
>>
>> On Sun, Jan 5, 2020 at 6:45 AM Ohad Alali via cfe-dev <
>> cfe-dev at lists.llvm.org> wrote:
>>
>>> Hi,
>>>
>>> I'm compiling my project with clang version 7.0.0-3.
>>> I added compilation flag frame-larger-than in order to warning using
>>> more than 1024 bytes.
>>>
>>> clang indeed warning as expected, but when I added -Werror in order to
>>> treat the warning as error clang ignore this flag and it stays warning.
>>>
>>> the compilation flags include also save-temps=obj, when I remove this
>>> flag the warning treated as error.
>>>
>>> Does save-temps flag should be related to -Werror or -Wframe-larger-than?
>>>
>>> full compilation flags:
>>> clang++-7 -D_SYS_LINUX_ -D_HOSTSYS_LINUX_ -D_CPU_  -D_SYS64_ -D_DEBUG_
>>> -O2  -Wframe-larger-than=1024 -MD -Wall -save-temps=obj -Wextra -Wshadow
>>> -Werror -g -ggdb -fPIC
>>>
>>> Thanks,
>>> Ohad
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20200125/782e1284/attachment.html>


More information about the cfe-dev mailing list